1. Field of the Invention
The present invention relates to a liquid supply member that supplies liquid to liquid ejection ports, a method for manufacturing the liquid supply member, and a method for manufacturing a liquid ejection head.
2. Description of the Related Art
Liquid supply members have supply passages through which liquid is supplied to liquid ejection ports and are used in, for example, inkjet recording heads which are typical as liquid ejection heads having ejection ports.
Referring to FIGS. 10A to 10C, the configuration of a known inkjet recording head will be simply described. An inkjet recording head H1001 is constituted by a tank holder unit H1003 and a recording element unit H1002 for ejecting ink. The tank holder unit H1003 is constituted by a tank holder H1500 and a supply passage plate H1510.
Ink that is supplied from an ink tank (not shown) is introduced to a recording element unit H1002 through an ink supply passage formed in a liquid supply member (ink supply member) provided in the tank holder unit H1003 and is supplied to ejection ports.
FIG. 10B is a bottom view of the tank holder H1500, and FIG. 10C is a top view of the supply passage plate H1510. The tank holder H1500 and the supply passage plate H1510 each have grooves H1600 to be formed into ink supply passages. The tank holder H1500 and the supply passage plate H1510 are joined such that the grooves H1600 overlap with each other, so that ink supply passages are formed in the ink supply member.
A known method for joining the tank holder H1500 and the supply passage plate H1510 is a laser welding method disclosed in Japanese Patent Laid-Open No. 2005-096422.
A method for joining the tank holder H1500 and the supply passage plate H1510 using this laser welding method will be described. First, the tank holder H1500 having a laser-light absorptive property and the supply passage plate H1510 having a laser-light transmissive property are brought into contact with each other using a presser jig. A contact portion 600 at which the tank holder H1500 and the supply passage plate H1510 come into contact with each other is provided next to the grooves H1600. Thereafter, the contact portion 600 is irradiated with laser light, with the tank holder H1500 and the supply passage plate H1510 being in contact, to join the two members, thereby forming ink supply passages.
The method for laser irradiation includes a scanning method and a simultaneous irradiation method.
The scanning method is a method involving scanning the locus of a desired joint surface with laser light having a reduced spot diameter emitted from a laser light irradiator. With this method, it takes a significant amount of time to scan the minute locus of the joint surface with laser light for welding.
On the other hand, the simultaneous irradiation method is a method involving irradiating a desired joint surface with laser light all at once, which can reduce the time involved in welding.
However, in particular, with the simultaneous irradiation method, heat that escapes from the contact portion 600 in the vicinity of the ends of the grooves H1600 in the longitudinal direction to the surroundings is higher than heat that escapes from the contact portion 600 in the vicinity of portions other than the ends. This may generate an unwelded portion at the contact portion 600 in the vicinity of the ends. The presence of the unwelded portion may cause ink leakage.